The morphological and biochemical analysis of hair roots and skin will be used as a sensitive criteria for the diagnosis of protein malnutrition in rats and monkeys with experimental protein malnutrition. The morphological techniques to be used in examining hairs include the anagen/telogen ratio, the hairs with present root sheaths, the diameter of the hair bulb, the amount of DNA and protein in the hair bulb, quantitative and qualitative differences in the high and low sulfur containing structural proteins of the hair bulbs, and the activity of various enzyme in the hair bulbs and skin. The in vitro synthesis of protein and nucleic acids will be measured in the hair bulbs as well. BIBLIOGRAPHIC REFERENCES: Ogawa, H. and Goldsmith, L.A.: Human epidermal transglutaminase. J. Invest. Derm. 68: 32-35, 1977. Morrison, D.M., and L.A. Goldsmith: Control of Ornithine decarboxylase in Rat skin. Clin. Res. 25: 284A, 1977. Presented at the American Federation of Clinical Research, Washington, D.C., May 1, 1977. Manuscript in preparation for the J. Invest. Derm.